The first goal of this research is to study the chemistry of the early events in hormone action. I propose to isolate and purify the vasopressin-sensitive adenylate cyclase from the canine renal medulla in order to study its physical and chemical properties. Purified adenylate cyclase will be used to make antibodies which will be used to examine the degree of similarity among adenylate cyclases from different cell types and the relation of adenylate to guanylate cyclase. The availability of specific antibodies will make possible the quantitation of adenylate cyclase so that the basis of abnormal levels of the enzyme such as are found in malignant cells or in other disease states may be studied. Eventually, the hormone receptor must be isolated as well, but these studies are the necessary first steps toward understanding the chemistry of the hormone receptor-adenylate cyclase interaction. The second goal of this project is to study the way vasopressin controls the permeability to water of the renal collecting duct. The hypothesis that this process is governed by phosphorylation of an intrinsic or extrinsic membrane protein will be tested. If it is correct, the protein will be isolated and characterized chemically. Its properties will be compared with other membrane proteins which mediate the passage of small molecules across the lipid bilayer such as the anion transport protein of the erythrocyte membrane. This is a start toward understanding the general problem of how plasma membrane permeability is controlled.